Ultrasound wound treatment method and device using standing waves

ABSTRACT

The method and device of the present invention for wound treatment with ultrasound standing waves includes a transducer probe to produce ultrasonic waves. The ultrasonic transducer has a tip with a distal radiation surface that radiates ultrasound energy toward the surface of a wound. Ultrasound standing waves occurring as a result of incident and reflected waves from the wound surface create ultrasonic radiation pressure. Ultrasound radiation pressure increases the blood flow in wound area, and ultrasound waves kill bacteria, stimulate healthy tissue cell and treat wounds.

FIELD OF INVENTION

[0001] The present invention relates to the treatment of wounds usingultrasound standing waves. In particular, the present invention relatesto a method and device of creating ultrasonic standing waves in air anddirecting them to a wound for delivering aerodynamic forces asultrasonic radiation pressure and ultrasonic waves as well. Ultrasoundradiation pressure increases the blood flow in the wound area, andultrasound waves kill bacteria, stimulate healthy tissue cells, andtreat the wound.

BACKGROUND OF THE INVENTION

[0002] Ultrasonic waves have been widely used in medical applications,including diagnostics and therapy as well as many industrialapplications, e.g., welding, cutting, fiber optics technology, speedmeters, etc. Diagnostic use of ultrasound waves includes usingultrasonic waves to detect underlying structures in an object or humantissue. In this method, an ultrasonic transducer is placed in contactwith the tissue or object via a coupling medium, and high frequency(1-10 MHz) ultrasonic waves are directed into the tissue. Upon contactwith the various underlying structures, the waves are reflected back toa receiver adjacent the transducer. By comparison of the signals of theultrasonic waves sent with the reflected ultrasonic wave as received, animage of the underlying structure can be produced. This technique isparticularly useful for identifying boundaries between components oftissue and can be used to detect irregular masses, tumors, etc.

[0003] Three therapeutic medical uses of ultrasound waves includeaerosol mist production, contact physiotherapy, and soft tissueablation. The ultrasound contact physiotherapy procedure may cause apatient significant discomfort and/or pain, and skin may appear raw anddamaged. Aerosol mist production makes use of a nebulizer or inhaler toproduce an aerosol mist for creating a humid environment and deliveringdrugs to the lungs.

[0004] Ultrasonic nebulizers operate by passing ultrasound waves ofsufficient intensity through a liquid, the waves being directed at anair-liquid interface of the liquid from a point underneath or within theliquid. Liquid particles are ejected from the surface of the liquid intothe surrounding air following the disintegration of capillary wavesproduced by the ultrasound. This technique can produce a very fine densefog or mist.

[0005] Aerosol mists produced by ultrasound are preferred because asmaller particle size of the aerosol can be obtained with the ultrasonicwaves. One of the major shortcomings of ultrasonic inhalers andnebulizers is that there is no directed aerosol to the target. An airstream is then required to direct the aerosol to the target, but thisdecreases the efficiency of ultrasound.

[0006] Ultrasonic sprayers (Sonic and Materials Inc., Misonix Inc.,Sono-Tek Inc., Zevex International, Inc., operate by passing liquidtrough central orifice of ultrasound instrument-tip. See, for example,U.S. Pat. Nos. 3,765,606; 4,659,014; 5,104,042; 4,9307,00; 4,153,201;4,655,393; 5,516,043; 5,835,678; 5,879,364; and 5,843,139.

[0007] Ultrasonic inhalers and drug delivery systems from Medisonic USA,Inc., 3M, Siemens Gmb, The Procter & Gamble Company, SheffieldPharmaceuticals, Aradigm, Inc., operate by atomizing liquid usingpiezoceramic film. See, for example, U.S. Pat. Nos. 4,294,407;5,347,998; 5,520,166; 5,960,792; 6,095,141; 6,102,298; 6,098,620;6,026,808; and 6,106,547.

OBJECT OF THE INVENTION

[0008] It is an object of the invention to provide an improved methodand device for treating wounds.

[0009] It is also an object of this invention to provide an improvedmethod and device for treating wounds using ultrasound standing waves.

[0010] It is a further object of the invention to provide a method anddevice for increasing blood flow, killing bacteria, and stimulatinghealthy tissue cell growth.

[0011] These and other objects of the invention will become moreapparent from the discussion below.

SUMMARY OF INVENTION

[0012] The present invention is a method and device for using ultrasonicstanding waves to treat wounds. Ultrasound standing waves occur as aresult of incident and reflected waves from a reflective surface thatare traveling in opposite directions. The resultant superposition of thetwo waves forms standing waves, which create ultrasonic radiationpressure. The standing waves, actually ultrasound radiation pressure,occur when the distance between (a) the distal end of a transducer (as aradiant of ultrasound waves) and (b) the reflected surface (e.g., awound surface) is: n×λ/2, where λ is the wave length and n is a positiveinteger. The standing waves are more effective in limited space or areaas a tube.

[0013] According to the invention ultrasound waves are created,directed, and delivered to a wound surface through the air to increaseblood flow, kill bacteria, stimulate healthy tissue cells and treatwounds with ultrasound energy. The method of treating wounds involvesthe use of ultrasound standing waves of a continuous or pulsedultrasound.

[0014] More particularly, the method of the invention comprisesproducing ultrasound standing waves using a free end surface of anultrasonic transducer and wound surface.

[0015] According to the method of the present invention, the radiationpressure of ultrasonic standing waves increase blood flow in wound areaand destroy the surface bacteria to result in a higher disinfectingproperty of ultrasound. Additionally, the ultrasound also stimulateshealthy cell growth to aid in granulization and epithelization of thehealing tissue. Other applications of the method can be directed tonon-medical uses such as cleansing, drying, sterilizing and coatingsurfaces of objects and food.

[0016] The method of the present invention offers an approach that mayre-establish use of some traditional ultrasound and establish a methodof treating wound and fighting bacteria without antibiotics whennecessary.

[0017] The overall concept of the present invention relates in methodand apparatus for wound treatment using ultrasonic standing wavesthrough air with no drug. This wound treatment method is possible withcombination of different energy sources as an ultrasound, laser,electric current, magnetic field, ultraviolet, microwaves, radiofrequency, etc.

BRIEF DESCRIPTION OF DRAWINGS

[0018]FIG. 1 is a perspective view of an ultrasound wound treatmentsystem with standing waves, according to the present invention;

[0019]FIG. 2 is a schematic, lateral cross-sectional view of anothertransducer useful with the system of FIG. 1.

[0020]FIG. 3 is a schematic, lateral cross-sectional view of atransducer having a bushing;

[0021]FIG. 4 is a schematic, lateral cross-sectional view of atransducer of FIG. 3 where the distal tip has been modified to provide afocussed beam; and

[0022]FIG. 5 is a schematic, lateral cross-sectional view of anembodiment of the invention intended to facilitate dissolution of bloodclots.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The present invention is a method and system, which usesultrasound standing wave energy to treat wounds. The system comprises agenerator of electrical signals and a handpiece having an ultrasoundtransducer and tip.

[0024] The invention can perhaps be better appreciated from thedrawings. A system for wound treatment according to present invention isillustrated in FIG. 1. The system 2 comprises a signal generator 4operatively or electrically connected through cable 6 to a transducer 8in a housing 10. Transducer 8 has an ultrasound tip 12 that generatesstanding ultrasound waves 14. Standing ultrasound waves 14 are directedto the surface 16 of a wound 18.

[0025] Standing ultrasound waves 14 occur when activated ultrasound tip12 is directed through the air to a wound surface 16 as a result ofincident and reflected waves from wound surface 16, which createsultrasonic radiation pressure. The distal end 20 of transducer tip 12(as a radiant of ultrasound waves) is preferably a distance d from woundsurface 16 (a source of reflected waves). Distance d is related to thewavelength λ of the ultrasound wave or signal by the formula

d=n×λ/2

[0026] where n is a positive integer. To reach this preferred distanceand therefore effect wound treatment practice, ultrasound transducer 8or tip 12 must frequently be moved back and forward toward wound surface16 by an operator.

[0027] The waveform of the ultrasound waves generated by transducer 8preferably corresponds to the waveform of the electrical signalsgenerated by signal generator 4. For example, electrical signals fromsignal generator 4 with rectangular, sinusoidal, trapezoidal, ortriangular waveforms will cause transducer 8 to produce respectivesimilarly shaped ultrasound waveforms.

[0028] The standing waves are more effective in limited space or areasuch as a tube. In each of FIGS. 3 to 5 a bushing 26 increasesultrasound radiation pressure. Bushing 26 may or may not be disposablepart on the distal end 28 of housing 10.

[0029] In the embodiment of the invention set forth in FIG. 4 the distalend 28 of ultrasonic tip 12 has been modified to a concave shape tofocus ultrasound waves 14.

[0030] One of the possible applications of the method of presentinvention is the facilitation of dissolution of blood clots by usingultrasound energy. In FIG. 5 ultrasound tip 12 is directed to a bloodvessel 30 with clot or clots 32. In this case ultrasound standing waves34 create cavitation inside blood vessel 30 and dissolve clot or clots32.

[0031] In another embodiment of the present invention a wound can alsobe treated with a gel or drug. After the gel or drug is applied to thewound surface, ultrasound standing waves would be directed to the wound.The drug would be activated and penetrate into tissue under ultrasoundradiation pressure.

[0032] Additional possible application of method using ultrasoundstanding waves is for the diffusion of grafts to a wound with radiationpressure gently.

[0033] The preceding specific embodiments are illustrative of thepractice of the invention. It is to be understood, however, that otherexpedients known to those skilled in the art or disclosed herein may beemployed without departing from the spirit of the invention or the scopeof the appended claims.

I claim:
 1. A method of treating a wound, comprising the step ofpositioning an ultrasound transducer having a distal radiation surfaceto direct an ultrasound standing wave at a surface of a wound, whereinthe distance d between distal radiation surface and the wound surface isdetermined by the formula d=n×λ/2 wherein λ is the wavelength of theultrasound standing wave and n is a positive integer.
 2. The method ofclaim 1, wherein the ultrasound transducer operates at a frequency offrom about 10 kHz to 10³ MHz.
 3. The method of claim 1, wherein d is atleast 0.1 in.
 4. The method of claim 1, wherein the ultrasoundtransducer is frequently moved back and forth in a longitudinaldirection by an operator to reach a preferred distance to create astanding wave.
 5. The method of claim 1, wherein the ultrasound standingwave creates radiation and/or pressure that energizes the wound.
 6. Themethod of claim 1, wherein in a prior step a gel, drug, or othermedicant is applied to the wound surface.
 7. The method of claim 6,wherein any medical effect of the gel, drug, or other medicant isenergized by the ultrasound standing wave.
 8. The method of claim 1,wherein the ultrasound standing wave has an ultrasound radiation,pressure, massage, and/or sterilization effect.
 9. A system for treatinga wound with ultrasound standing waves, comprising a generator forgenerating ultrasound waves, an ultrasound transducer operativelyconnected to said generator and having a distal radiation surface, andmeans for adjusting the distance between the distal radiation surfaceand a surface of a wound to create ultrasound standing waves.
 10. Thesystem of claim 9, wherein the ultrasound transducer operates at afrequency of from about 10 KHz to 10³ MHz.
 11. The system of claim 9,wherein the distal end of the ultrasound transducer comprises a bushing.12. The system of claim 9, wherein the ultrasound frequency ismodulated.
 13. The system of claim 9, wherein the ultrasound frequencyis pulsed.
 14. The system of claim 9 wherein the waveform of theultrasound wave is sinusoidal.
 15. The system of claim 9, wherein thewave form of the ultrasound wave is rectangular.
 16. The system of claim9, wherein the wave form of the ultrasound wave is trapezoidal.
 17. Thesystem of claim 9, wherein the waveform of the ultrasound wave istriangular.
 18. The system of claim 9, wherein the ultrasound beam isfocussed.